TITLE: GCN CIRCULAR NUMBER: 18673 SUBJECT: GRB 130831A: MASTER early OT detection and LC DATE: 15/12/07 14:17:09 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs E.Gorbovskoy, V. Lipunov, N.Tyurina, V.Kornilov, P.Balanutsa, A.Kuznetsov, D.Kuvshinov Lomonosov Moscow State University, Sternberg Astronomical Institute K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University After this observation night there was no electricity at the Tunka observatory for a few days . Therefore, the data were not immediately available. We forgot to check the follow-up after power is restored and rediscovered this source as optical transient during the data reprocessing of the present time. MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Tunka was pointed to the GRB130831A 58 sec after trigger time at 2013-08-31 13:05:14 UT. On our second (20s exposure 120 sec after trigger) set we found 1 optical transient within SWIFT error-box (ra=23 54 36 dec=+29 27 00 r=0.05) brighter then 15.1. T-Tmid Date Time Expt. Ra Dec Mag -------|-----------|----------|-------|-----------------|-----------------|------- 130 2013-08-31 13:06:16 20 23h 54m 29.82s +29d 25m 47.1s 14.34 The 5-sigma upper limit has been about 15.1mag The automatic reduction data are below: date time coord2000 Exp. Polaroid mag err UT s 2013-08-31 13:05:13 - - 10 P/ >15.4 2013-08-31 13:05:14 - - 10 P\ >15.5 2013-08-31 13:06:14.969 23h 54m 29.77s +29d 25m 46s.5 20 P/ 14.19 0.13 2013-08-31 13:06:16.09 23h 54m 29.82s +29d 25m 47s.1 20 P\ 14.34 0.15 2013-08-31 13:07:37.707 23h 54m 29.94s +29d 25m 46s.6 40 P 13.70 0.07 2013-08-31 13:07:38.411 23h 54m 29.89s , +29d 25m 46s.3 40 P 14.08 0.08 2013-08-31 13:09:21.157 23h 54m 29.87s , +29d 25m 46s.5 60 P 13.96 0.06 2013-08-31 13:09:22.329 23h 54m 29.86s , +29d 25m 46s.3 60 P 14.17 0.06 2013-08-31 13:11:11.731 23h 54m 29.87s , +29d 25m 46s.8 80 P 13.96 0.05 2013-08-31 13:11:12.656 23h 54m 29.87s , +29d 25m 46s.4 80 P 14.05 0.04 2013-08-31 13:13:26.831 23h 54m 29.87s , +29d 25m 46s.4 110 P 13.14 0.02 2013-08-31 13:13:26.904 23h 54m 29.87s , +29d 25m 46s.7 110 P 13.23 0.01 2013-08-31 13:16:22.741 23h 54m 29.88s , +29d 25m 46s.4 140 P 12.76 0.01 2013-08-31 13:16:23.769 23h 54m 29.89s , +29d 25m 46s.7 140 P 12.79 0.01 2013-08-31 13:19:48.725 23h 54m 29.88s , +29d 25m 46s.5 180 P 13.10 0.01 2013-08-31 13:19:49.319 23h 54m 29.89s , +29d 25m 46s.6 180 P 13.03 0.01 2013-08-31 13:23:42.166 23h 54m 29.89s , +29d 25m 46s.6 180 P 13.44 0.01 2013-08-31 13:23:43.007 23h 54m 29.89s , +29d 25m 46s.6 180 P 13.40 0.01 2013-08-31 13:27:40.436 23h 54m 29.90s , +29d 25m 46s.5 180 P 13.80 0.01 2013-08-31 13:27:41.309 23h 54m 29.89s , +29d 25m 46s.7 180 P 13.79 0.01 2013-08-31 13:31:39.264 23h 54m 29.88s , +29d 25m 46s.7 180 P 14.08 0.02 2013-08-31 13:31:39.957 23h 54m 29.88s , +29d 25m 46s.8 180 P 14.12 0.01 2013-08-31 13:36:03.651 23h 54m 29.89s , +29d 25m 46s.4 180 P 14.44 0.02 2013-08-31 13:36:04.486 23h 54m 29.89s , +29d 25m 46s.5 180 P 14.51 0.02 2013-08-31 13:39:59.065 23h 54m 29.88s , +29d 25m 46s.6 180 P 14.55 0.02 2013-08-31 13:39:59.918 23h 54m 29.89s , +29d 25m 46s.7 180 P 14.53 0.02 2013-08-31 13:44:00.574 23h 54m 29.89s , +29d 25m 46s.7 180 P 14.72 0.02 2013-08-31 13:44:01.425 23h 54m 29.89s , +29d 25m 46s.6 180 P 14.78 0.03 2013-08-31 13:48:10.668 23h 54m 29.91s , +29d 25m 46s.5 180 P 14.94 0.03 2013-08-31 13:48:11.488 23h 54m 29.87s , +29d 25m 46s.5 180 P 14.95 0.02 2013-08-31 13:52:19.736 23h 54m 29.89s , +29d 25m 46s.3 180 P 14.97 0.03 2013-08-31 13:52:20.267 23h 54m 29.88s , +29d 25m 46s.3 180 P 14.99 0.03 2013-08-31 13:56:25.283 23h 54m 29.89s , +29d 25m 46s.7 180 P 15.11 0.03 2013-08-31 13:56:25.394 23h 54m 29.88s , +29d 25m 46s.6 180 P 15.05 0.03 2013-08-31 14:00:30.776 23h 54m 29.88s , +29d 25m 46s.7 180 P 15.16 0.03 2013-08-31 14:00:31.465 23h 54m 29.88s , +29d 25m 46s.6 180 P 15.13 0.03 2013-08-31 14:04:35.057 23h 54m 29.88s , +29d 25m 46s.5 180 P 15.18 0.03 2013-08-31 14:04:37.274 23h 54m 29.90s , +29d 25m 46s.8 180 P 15.10 0.03 2013-08-31 14:08:42.051 23h 54m 29.88s , +29d 25m 46s.6 180 P 15.18 0.03 2013-08-31 14:08:42.358 23h 54m 29.89s , +29d 25m 46s.8 180 P 15.18 0.03 2013-08-31 14:13:16.808 23h 54m 29.88s , +29d 25m 46s.5 180 P 15.16 0.03 2013-08-31 14:13:17.534 23h 54m 29.87s , +29d 25m 46s.6 180 P 15.19 0.03 2013-08-31 14:17:26.33 23h 54m 29.88s , +29d 25m 46s.6 180 P 15.22 0.03 2013-08-31 14:17:26.78 23h 54m 29.89s , +29d 25m 46s.7 180 P 15.16 0.03 2013-08-31 14:21:33.6 23h 54m 29.87s , +29d 25m 46s.4 180 P 15.33 0.03 2013-08-31 14:21:34.446 23h 54m 29.89s , +29d 25m 46s.6 180 P 15.27 0.03 2013-08-31 14:26:01.003 23h 54m 29.90s , +29d 25m 46s.7 180 P 15.37 0.03 2013-08-31 14:26:01.882 23h 54m 29.89s , +29d 25m 46s.5 180 P 15.30 0.03 2013-08-31 14:29:49.129 23h 54m 29.89s , +29d 25m 46s.7 180 P 15.45 0.03 2013-08-31 14:29:50.359 23h 54m 29.87s , +29d 25m 46s.7 180 P 15.39 0.03 2013-08-31 14:33:42.843 23h 54m 29.90s , +29d 25m 46s.4 180 P 15.47 0.03 2013-08-31 14:33:43.028 23h 54m 29.89s , +29d 25m 47s.0 180 P 15.46 0.04 2013-08-31 14:37:43.134 23h 54m 29.87s , +29d 25m 46s.4 180 P 15.52 0.04 2013-08-31 14:37:44.1 23h 54m 29.87s , +29d 25m 46s.6 180 P 15.42 0.04 2013-08-31 14:41:37.936 23h 54m 29.90s , +29d 25m 46s.5 180 P 15.66 0.04 2013-08-31 14:41:40.554 23h 54m 29.90s , +29d 25m 46s.5 180 P 15.57 0.04 2013-08-31 14:45:27.386 23h 54m 29.89s , +29d 25m 46s.4 180 P 15.71 0.04 2013-08-31 14:45:28.83 23h 54m 29.92s , +29d 25m 46s.7 180 P 15.54 0.04 2013-08-31 14:49:23.464 23h 54m 29.88s , +29d 25m 46s.6 180 P 15.70 0.04 2013-08-31 14:49:24.934 23h 54m 29.89s , +29d 25m 46s.6 180 P 15.58 0.04 2013-08-31 14:53:18.194 23h 54m 29.88s , +29d 25m 46s.4 180 P 15.66 0.04 2013-08-31 14:53:18.686 23h 54m 29.90s , +29d 25m 46s.8 180 P 15.58 0.04 2013-08-31 14:57:36.995 23h 54m 29.87s , +29d 25m 46s.3 180 P 15.76 0.04 2013-08-31 14:57:37.418 23h 54m 29.90s , +29d 25m 46s.6 180 P 15.63 0.04 2013-08-31 15:01:42.896 23h 54m 29.91s , +29d 25m 46s.3 180 P 15.88 0.05 2013-08-31 15:01:43.521 23h 54m 29.92s , +29d 25m 46s.6 180 P 15.69 0.04 2013-08-31 15:05:42.207 23h 54m 29.88s , +29d 25m 46s.6 180 P 15.95 0.04 2013-08-31 15:05:43.764 23h 54m 29.89s , +29d 25m 46s.7 180 P 15.75 0.04 2013-08-31 15:09:53.777 23h 54m 29.89s , +29d 25m 46s.4 180 P 15.93 0.05 2013-08-31 15:09:54.9 23h 54m 29.90s , +29d 25m 46s.5 180 P 15.84 0.05 2013-08-31 15:14:14.225 23h 54m 29.90s , +29d 25m 46s.5 180 P 16.04 0.05 2013-08-31 15:14:14.636 23h 54m 29.88s , +29d 25m 46s.5 180 P 15.90 0.05 2013-08-31 15:18:32.515 23h 54m 29.88s , +29d 25m 46s.4 180 P 15.98 0.05 2013-08-31 15:18:32.972 23h 54m 29.62s , +29d 25m 46s.7 180 P 16.80 0.08 2013-08-31 15:22:42.728 23h 54m 29.86s , +29d 25m 46s.4 180 P 16.13 0.05 2013-08-31 15:22:43.005 23h 54m 29.72s , +29d 25m 47s.5 180 P 16.50 0.08 2013-08-31 15:27:06.639 23h 54m 29.88s , +29d 25m 46s.1 180 P 16.23 0.06 2013-08-31 15:27:07.166 23h 54m 29.90s , +29d 25m 46s.6 180 P 15.99 0.06 2013-08-31 15:31:14.164 23h 54m 29.89s , +29d 25m 46s.5 180 P 16.32 0.06 2013-08-31 15:31:14.663 23h 54m 29.89s , +29d 25m 47s.1 180 P 16.06 0.06 2013-08-31 15:35:08.964 23h 54m 29.87s , +29d 25m 46s.4 180 P 16.39 0.07 2013-08-31 15:35:10.803 23h 54m 29.97s , +29d 25m 49s.0 180 P 16.83 0.10 2013-08-31 15:39:37.457 23h 54m 29.89s , +29d 25m 46s.7 180 P 16.47 0.07 2013-08-31 15:39:38.229 23h 54m 29.84s , +29d 25m 48s.1 180 P 16.73 0.10 2013-08-31 15:43:50.963 23h 54m 29.89s , +29d 25m 46s.6 180 P 16.51 0.07 2013-08-31 15:43:51.628 23h 54m 29.68s , +29d 25m 46s.2 180 P 17.30 0.14 2013-08-31 15:47:41.439 23h 54m 29.92s , +29d 25m 46s.8 180 P 16.41 0.08 2013-08-31 15:47:41.868 23h 54m 29.70s , +29d 25m 46s.3 180 P 16.70 0.10 2013-08-31 15:51:28.744 23h 54m 29.89s , +29d 25m 46s.7 180 P 16.57 0.08 2013-08-31 15:51:29.974 23h 54m 29.69s , +29d 25m 45s.8 180 P 16.99 0.12 2013-08-31 15:55:28.935 23h 54m 29.91s , +29d 25m 46s.6 180 P 16.68 0.11 2013-08-31 15:55:29.91 23h 54m 29.92s , +29d 25m 46s.6 180 P 16.36 0.10 2013-08-31 15:59:32.081 23h 54m 29.88s , +29d 25m 46s.5 180 P 16.78 0.09 2013-08-31 15:59:32.882 23h 54m 29.77s , +29d 25m 45s.2 180 P 16.75 0.10 2013-08-31 16:03:45.019 23h 54m 29.89s , +29d 25m 46s.2 180 P 16.71 0.09 2013-08-31 16:03:45.878 23h 54m 29.73s , +29d 25m 49s.2 180 P 16.98 0.13 2013-08-31 16:03:45.878 23h 54m 29.67s , +29d 25m 45s.0 180 P 17.21 0.14 2013-08-31 16:07:40.752 23h 54m 29.87s , +29d 25m 46s.7 180 P 16.68 0.10 2013-08-31 16:07:40.756 23h 54m 29.85s , +29d 25m 46s.9 180 P 16.53 0.11 2013-08-31 16:11:45.003 23h 54m 29.89s , +29d 25m 46s.5 180 P 16.65 0.09 2013-08-31 16:11:46.074 23h 54m 29.68s , +29d 25m 47s.0 180 P 16.51 0.11 2013-08-31 16:16:04.472 23h 54m 29.89s , +29d 25m 46s.2 180 P 16.90 0.11 2013-08-31 16:16:05.21 23h 54m 29.71s , +29d 25m 46s.2 180 P 17.15 0.14 2013-08-31 16:20:16.552 23h 54m 29.88s , +29d 25m 46s.4 180 P 16.71 0.09 2013-08-31 16:20:16.892 23h 54m 29.90s , +29d 25m 47s.3 180 P 16.63 0.12 2013-08-31 16:24:28.011 23h 54m 29.92s , +29d 25m 46s.2 180 P 16.74 0.12 2013-08-31 16:24:28.419 23h 54m 29.64s , +29d 25m 46s.9 180 P 17.97 0.22 2013-08-31 16:28:38.273 23h 54m 29.91s , +29d 25m 46s.3 180 P 16.75 0.11 2013-08-31 16:28:39.181 23h 54m 29.66s , +29d 25m 47s.7 180 P 17.10 0.16 2013-08-31 16:32:35.03 23h 54m 29.88s , +29d 25m 46s.4 180 P 17.03 0.12 2013-08-31 16:36:41.311 23h 54m 29.91s , +29d 25m 46s.9 180 P 16.88 0.13 2013-08-31 16:36:41.982 23h 54m 29.90s , +29d 25m 45s.2 180 P 16.91 0.14 2013-08-31 16:40:40.333 23h 54m 29.85s , +29d 25m 46s.5 180 P 17.07 0.15 2013-08-31 16:40:40.788 23h 54m 29.80s , +29d 25m 46s.5 180 P 18.57 0.32 The automatic light curve is available at http://observ.pereplet.ru/images/GRB130831A.jpg The message may be cited.